the :union: of two different dental sprouts which can happen in any phase of dental development is commonly called fusion. this developmental anomaly may cause clinical problems including esthetic impairment, which are mainly treated by endodontic and surgical treatments. there are a few reports of conservative not invasive treatment of fused incisors teeth through restorative or prosthetic tec...

In this paper, a reaction system consisting of two parallel, non-isothermal autocatalytic reactions in a Continuous Stirred Tank Reactor (CSTR) has been considered. Reactor chaotic behavior is possible for certain values of system parameters. Two types of controllers are designed and compared in order to control both the reactor temperature and the product concentration. T...

milk is often described as a complete food because it contains protein, sugar, fat, vitamins, and minerals. this study was performed to investigate risk factors affecting chemical and bacteriological quality of bulk tank milk. according to the following conducted experiments, the milk was divided into two standard and non-standard groups. then, effect of risk factors on making the samples non-s...

The humidifier disinfectant disaster (HDD) was not a simple poisoning accident by biocides, but a singular disaster in history created by chemicals in household products. This disaster was a result of the failure of a system for the management of chemical and product safety. Since the management authority for chemical usage safety is different from those for chemical safety in products, many bl...

The ‘managed-metabolism’ hypothesis suggests that a ‘cooperation barrier’ must be overcome if self-producing chemical organizations are to undergo the transition from non-life to life. This dynamical barrier prevents un-managed, selforganizing, autocatalytic networks of molecular species from individuating into complex, cooperative organizations. The barrier arises because molecular species tha...

growth of the petrochemical industry and its products has been followed growth in other sectors of production, use and trade of chemicals at national and regional levels. it is one of the basic industries which are feeder to other industry sectors as the engine of the economy and play a major role in developing countries. with no doubt mismanagement and improper use of chemicals lead to harmful...

In positive systems, inputs, state variables and outputs take only non-negative values. Examples of positive systems are industrial processes involving chemical reactors, heat exchangers and distillation columns, storage systems, compartmental systems, or water and atmospheric pollution models. A variety of models revealing the behaviour of positive linear systems can be found in engineering, m...

In positive systems, the inputs, state variables and outputs take only non-negative values. Examples of positive systems are industrial processes involving chemical reactors, heat exchangers and distillation columns, storage systems, compartmental systems, or water and atmospheric pollution models. A variety of models having positive linear system behaviour can be found in engineering, manageme...

Soil solarization is a special mulching process which causes hydrothermal disinfestation and other physical and biological changes in soil which are beneficial to plant health and growth. Plastic film laid over moist soil during periods of high air temperature, usually for l-2 months, can greatly reduce or eradicate a number of pathogens and pests including fungi, bacteria, nematodes, arthropod...